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Gas Chromatography
Main Article (issue 19.09)
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| Main Article Featured in Issue 19.9 |
| Reduce Your Risk: Prevent GC Inlet Problems BEFORE They Cost You Time and Money! |
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 Gas chromatography users will reduce the risk of chromatographic problems and instrument downtime through regular, proper maintenance of the GC injection port. Our technical service chemists help GC users solve problems daily that are the direct result of dirty liners, over used septa, or improperly installed ferrules. This article discusses how some simple, routine preventative maintenance of your injection port system will prevent costly problems down the line. Be proactive with your maintenance today or be sorry with your results tomorrow.
Change your Septum Daily
You should routinely inspect and replace your injection port septum to reduce the risk of leaks and septa particle contamination. Change the septum daily, especially if the instrument is in heavy use. Repeated use of the same septum will result in increased coring, which will introduce a leak and result in septa fragments contaminating the injection port. Pieces of septa in the injection port will introduce extra peaks as shown in Figure A. If using a mass spectrometer, you will see a mass spectrum of the septa bleed, as shown in Figure B.Change Ferrules during System Maintenance and Column Installation
You should always replace the column ferrules when you install a new column or perform column maintenance. A leaking ferrule will allow oxygen into the carrier gas, shortening your column life. A leak can also cause variation in retention times, baseline drift, and sample loss. Be aware that small particles nearly always enter the capillary column during ferrule installation. Ferrule fragments will cause bleed problems or absorb sample components leading to poor results. Be sure to follow our column installation instructions to avoid ferrule fragments from entering the column. Proper ferrule installation and maintenance will minimize your risk of leaks, bleed, and poor reproducibility.
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Routinely Inspect and Change Dirty Liners
GC users should routinely inspect and replace the inlet liner to eliminate contaminants and active sites that will lead to poor chromatography. Dirty samples passing through the liner leave behind residue. As residues accumulate, they affect chromatography by adsorbing the sample components of interest to you. This adsorption results in poor peak shapes, and sometimes, extra peaks in the chromatogram. This leads to rework, wasted time, lost money and inaccurate results. You should inspect your liner regularly, if not daily, and replace it with a new, deactivated liner if residue is present or your performance test mix fails. Figure C shows how active sites in a dirty liner can affect your results.Inexpensive Maintenance Saves Time and Money in the Long Run
GC users often overlook or disregard the importance of preventative maintenance and only act when a problem is obvious. We have highlighted three important injection port components that require proactive attention to reduce your risk of problems. You should check and replace the inlet liner, septa, and column ferrules regularly, particularly when installing a new column. Supelco can help you prevent the problems discussed. We offer a complete line of high quality, injection port accessories. Choosing Supelco’s performance accessories for routine GC system maintenance and new column installation will save you costly downtime, rework, and inaccurate results. Remember that an ounce of prevention is worth a pound of cure. |
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For more information, see |
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T112853 (849 KB)  "Capillary Troubleshooting Guide" |
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T400008 (1446 KB) "Capillary GC Troubleshooting" |
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T401027 (69 KB) "Capillary Injector Products for Agilent Technologies GCs |
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